山东重大基础地质问题研究进展

Research progress on major basic geological problems in Shandong Province.

在1∶50万山东省大地构造相图编制和大地构造相综合研究的基础上,作者对山东重大基础地质问题提出了新的划分方案。山东地块是经多期增生和碰撞、镶嵌、叠覆而成的,其漫长的地质构造演化具明显的阶段性,可分为前南华纪、南华纪——中三叠世和晚三叠世——第四纪三大构造演化阶段。大地构造分区分为陆块区、造山系和叠加造山——裂谷系,划分出3个I级构造单元、5个II级构造单元、18个III级构造单元和55个IV级构造单元。基于鲁东和鲁西地区在地层建造、岩浆活动、构造格局和成矿作用等存在的重大差异性,新厘定的渤海陆块作为华北陆块区之下的II级构造单元。厘定大别——苏鲁造山带的北部边界、鲁西陆块与渤海陆块的边界。对古元古代荆山群、粉子山群形成的构造环境进行了深入探讨,认为是弧后盆地靠近大陆边缘一侧的构造背景,在古元古代晚期的造山过程中,粉子山群和荆山群等均卷入了造山过程,其中荆山群发生了深俯冲及高压麻粒岩相变质作用。胶东地区构造——岩浆事件和金矿成矿作用受控于特提斯、古亚洲洋和太平洋三大构造域,金矿形成于中生代构造体制转折和岩石圈减薄的动力学背景,与华北板块和扬子板块碰撞及太平洋板块的俯冲机制存在密切成因关系。

Based on drawing up of the 1500000 tectonic facies map of the Shandong Province and the comprehensive research, a new proposal about the tectonic evolution of the Shandong Province has been put forward. The Shandong block was formed through multi-episodes of accretion, collision, mosaic and superposition, which can be divided into three major tectonic evolution stages： Pre-Nanhua Period, Nanhua to Middle Triassic Period, Late Triassic to Quaternary Period. Geotectonic units include cratonic systems, orogenic systems and superimposed orogenic-rift systems, and three grade I tectonic units, five grade II tectonic units, eighteen grade III tectonic units and fifty-five grade IV tectonic units have been recognized. Based on the pronounced differences of stratigraphy, igneous activities, structural framework and mineralization between the western and eastern Shandong, the newly recognized Bohai block is thought as a grade II tectonic unit under the North China Block. North boundary of the Dabie-Sulu orogenic belt and boundary between the western Shandong block and the Bohai block have been determined. The Paleoproterozoic Jinshan and Fenzishan groups were thought to be formed in a back-arc basin located on the continental margin and then both of them were involved in the orogenic process in the Paleoproterozoic. The Jingshan Group has also experienced deep-subduction and high-pressure granulite-facies metamorphism. Tectonic-thermal events and gold-mineralization in the eastern Shandong were controlled by the Tethys, Paleo-Asian Ocean and Pacific Ocean. Gold ore was formed in the Mesozoic transformation of tectonic regime and lithosphere thinning, strongly related with the collision between the North China and South China blocks and subduction of the Pacific plate.